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W Wichmann

Publications and source records attributed to W Wichmann.

At least 19 recordsLinked to original sources
PubMed1999

3D T2-weighted fast spin-echo MRI sialography of the parotid gland.

The diagnostic value of 3D T2-weighted MRI sialography and 2D T2-weighted fast spin-echo (FSE) images for delineation of the normal duct system and characterisation of parotid gland duct pathology was compared in a prospective study. We studied eight healthy volunteers and 18 patients with pathology of the parotid gland (tumours in 3, sialolithiasis in 6, Sjögren's disease in 4, recurrent or chronic parotitis in 4, post-traumatic stricture of the main parotid duct in 1). A heavily T2-weighted 3D FSE sequence was compared with a conventional 2D T2-weighted FSE sequence. The normal main parotid duct was always visible on 3D sialography and seen in 68% of the 2D T2-weighted FSE studies. The diagnostic reliability of both sequences for diagnosis of luminal concretions in sialolithiasis and dilatation of the duct in duct stricture or chronic parotitis was equal, although slight intraglandular dilatation was appreciated only on 3D sialography. Extraductal pathology resulting in obstruction or displacement of ducts was better characterised on 2D T2-weighted images. However, 3D MRI sialography offered the advantage of postprocessing with overview images and multiple maximum-intensity projection images in any plane.

Adolescent↗
PubMed1998

T2-weighted three-dimensional fast spin-echo MR in inflammatory peripheral facial nerve palsy.

PURPOSE: Our objective was to identify histologically and intraoperatively verified focal nerve thickening of the distal intrameatal segment on three-dimensional fast spin-echo (FSE) T2-weighted MR images as a new diagnostic criterion in patients with inflammatory peripheral facial nerve palsy. METHODS: Twenty-two patients with clinically diagnosed unilateral (n = 20) or bilateral (n = 2) inflammatory peripheral facial nerve palsy were examined on a 1.5-T MR imager using noncontrast and contrast-enhanced T1-weighted SE sequences and 3-D T2-weighted FSE sequences with secondary reformations. Abnormal contrast enhancement and possible focal nerve thickening of the distal intrameatal segment, labyrinthine nerve segment, and geniculate ganglion region were analyzed prospectively. RESULTS: In all patients, the T1-weighted postcontrast SE images showed characteristic smooth, linear, abnormally intense contrast enhancement of the distal intrameatal segment, indicating peripheral inflammatory nerve palsy. In 23 nerves (96%) a focal bulbous nerve thickening of the distal intrameatal segment was observed on 3-D T2-weighted FSE images. In 100% of patients with peripheral inflammatory facial nerve palsy, postcontrast T1-weighted SE images showed a smooth, linear, and abnormally intense contrast enhancement of the distal intrameatal segment; reformatted very thin 3-D T2-weighted FSE images showed a focal bulbous nerve thickening of the distal intrameatal segment in 96% of patients. These findings corresponded to intraoperative and histologic findings. CONCLUSION: Three-dimensional T2-weighted FSE sequences are fast and cheap compared with T1-weighted postcontrast images, but secondary reformations are time-consuming and require exact anatomic knowledge for careful analysis of the different nerve segments.

Adolescent↗
PubMed1997

Escher-Hirt syndrome.

A mother and her two daughters are reported with bilateral conductive deafness due to incudo-stapedial abnormalities, and microtia with thickened ear lobes. This pattern of abnormal findings, transmitted with an autosomal dominant mode of inheritance, is characteristic of the Escher-Hirt syndrome. One of the daughters died from an additional cardiac malformation (VSD). Anomalies of the middle ear were demonstrated in the surviving patients by computed tomography. Differential diagnosis with other genetic syndromes associated with deafness, and possible therapeutic approaches are discussed.

Adult↗
PubMed1997

MR differentiation of adamantinous and squamous-papillary craniopharyngiomas.

PURPOSE: To determine MR criteria for differentiating adamantinous from squamous-papillary craniopharyngiomas. METHODS: The MR imaging features of 42 histologically proved craniopharyngiomas (25 adamantinous, 15 squamous-papillary, and two mixed subtypes) were examined with multiplanar T2-weighted and noncontrast and contrast-enhanced T1-weighted imaging. Differences in the mR features of both subtypes were evaluated retrospectively. RESULTS: The adamantinous craniopharyngioma is a mixed solid-cystic or mainly cystic lobulated suprasellar or intrasellar/suprasellar tumor occurring in children and adults, typically with large nonenhancing hyperintense cysts on T1-weighted images. The squamous-papillary craniopharyngioma is a predominantly solid or mixed solid-cystic suprasellar tumor occurring in adults, appearing as a hypointense cyst on noncontrast T1-weighted images. Calcifications and recurrent tumors are more often observed in adamantinous tumors but can be seen in squamous-papillary tumors as well. Statistically significant parameters useful for differentiating the two tumor subtypes are the encasement of vessels, the lobulated shape, and the presence of hyperintense cysts in adamantinous tumors, and the round shape, the presence of hypointense cysts, and the predominantly solid appearance in squamous-papillary tumors. CONCLUSION: Craniopharyngiomas can be divided into two clinically, histologically different subtypes, which suggests a different pathogenesis of these two types of tumor.

Adolescent↗
PubMed1997

Aneurysm clips made of titanium: magnetic characteristics and artifacts in MR.

PURPOSE: To evaluate the magnetic characteristics, artifact formation, and implant safety of titanium aneurysm clips for use in MR imaging. METHODS: Aneurysm clips made of titanium alloy TiAl6V4 were tested in a magnetometer to determine their magnetic susceptibility and in a 1.5-T MR imager using both a geometric phantom and an animal model. A commercially available alpha-Phynox clip served as the reference standard. RESULTS: We found minimal magnetization and a significant reduction in image artifacts with the titanium clip as compared with the Phynox clip. CONCLUSION: The titanium clips improve image quality, biocompatibility, and patient safety in medical MR applications.

Aneurysm↗
PubMed1996

Cerebellomedullary compression in recessive craniometaphyseal dysplasia.

Craniometaphyseal dysplasia (CMD) is a very rare disorder of bone remodelling characterised by sclerosis of the skull base, vault and facial bones and metaphyseal splaying of tubular bones. The recessive form appears to be more severe than the dominant. Cranial nerve deficits have been reported in infancy and early childhood in a few patients, but the long-term history of recessive CMD is not well documented. We report cerebellomedullary compression in a girl with recessive CMD recognised at 14 years because of progressive truncal ataxia. MRI revealed backward angulation of the thickened clivus, narrowing of the foramen magnum and upward deviation of the cerebellum by a markedly thickened occipital squama, tonsillar herniation and obliteration of the infratentorial cerebrospinal fluid spaces. Posterior cranial fossa decompression resulted in marked improvement of the ataxia. Compression of posterior cranial fossa structures has to be considered in the natural history and management of CMD.

Brain Diseases↗
PubMed1996

[Inflammatory facial paralysis in MRI. An overview].

In inflammatory peripheral facial nerve palsy pathologically intense, linear and smooth enhancement of the distal intrameatal nerve segment can always be observed on T1-w- SE- MR sequences. The other nerve segments often present with a pathological enhancement as well. On T2-w- SE sequences, a thickening of the distal intrameatal nerve segment can be observed. The pathological enhancement persists over weeks and months; even in patients with complete clinical recovery, a persistent enhancement of the distal intrameatal nerve segment can be demonstrated. No correlation can be established between the intensity of the enhancement, the clinical condition and the electrophysiological data on electroneurography. The persistent enhancement of the different nerve segments is due to a long-lasting breakdown of the blood-peripheral nerve-barrier related to the process of degeneration and regeneration of the facial nerve in inflammatory palsy.

Contrast Media↗
PubMed1996

[Inflammatory diseases of the spinal cord and spinal nerve roots in the MRI].

PURPOSE: To evaluate characteristic and reliable MRI patterns of different inflammatory lesions of the spinal cord and the nerve roots in immunologically compromised and immunologically competent patients in order to be able to establish a correct diagnosis based on MRI findings. MATERIAL AND METHODS: The MRI examinations of 52 patients (27 men, 25 women, mean age 38.5 years, range 14-75 years) with proven inflammatory lesions (39 patients) or tumorous/postactinic lesions of the spinal cord (6 patients) and vascular malformations of the spinal cord (7 patients) were retrospectively analyzed. All examinations were performed on a 1.5 T MR unit, using bi- or triplanar T1-w pre- and postcontrast as well as T2-w SE sequences. Additionally, a review of the common medical literature concerning inflammatory lesions of the spinal cord was included. RESULTS: Clinical and radiological examinations allow a subdivision of inflammations of the spinal cord and the nerve roots into (meningoradiculo) myelitis and meningoradiculo (myelitis) in immunologically suppressed or competent patients. The MRI patterns of these two inflammatory subtypes vary: meningoradiculitis presents with an enhancement of the nerve roots and the leptomeninges; myelitis itself is characterized by single or multiple, diffuse or multifocal, with or without nodular, patchy or diffusely enhancing intramedullary lesions, with or without thickening of the cord and leptomeningeal inflammation. This differentiation helps to determine the underlying etiology in some of the patients. The immunologically suppressed patient suffers from viral infections (especially herpes simplex, varicella-zoster virus, cytomegalovirus), bacterinal infections (tuberculosis), but rarely from parasitic infections. The immunologically competent patient suffers from bacterial (borreliosis), but rarely viral infections, sarcoidosis and demyelinating diseases. Idiopathic myelitis is also common. CONCLUSIONS: Secondary ischemic and demyelinating processes result in a complex morphology of inflammatory lesions on MRI, and therefore the whole spectrum of demyelinating, ischemic and inflammatory lesions has to be included in the differential diagnosis. Even tumors may imitate inflammatory myelitis and radiculitis. Most commonly, meningoradiculitis can be separated from myelitis. A reliable diagnosis of a specific inflammatory lesion is difficult and is mostly achieved in patients with multiple sclerosis and in patients with HIV-associated cytomegalovirus infection.

AIDS-Related Opportunistic Infections↗
PubMed1996

Posterior chamber myopia lenses in phakic eyes.

OBJECTIVE: To determine the best technique for implanting a hypernegative intraocular lens (IOL) in the posterior chamber of phakic eyes to neutralize high myopia and its results. SETTING: Robert Koch Hospital, Hannover-Gehrden, Germany. METHODS: We implanted the Chiron-Adatomed silicone myopia IOL in 69 eyes of 37 patients between June 1992 and August 1994 and followed them prospectively. RESULTS: To avoid marked decentration, the IOL should merely touch the ciliary sulcus. Its best length should equal the horizontal diameter of the cornea (white to white). Iritis from implantation trauma was avoided by intravenous administration of 250 mg prednisone preoperatively. When inserting the Chiron-Adatomed myopia IOL, we avoided putting pressure on the crystalline lens with the spatula. In 53 eyes, the difference between precalculated postoperative refraction and achieved postoperative refraction at 3 months was +0.07 +/- 1.05 diopters (D) (mean +/- SD). No eye deviated more than 2.80 D. Eleven of 69 eyes had a follow-up of fewer than 6 months and 13 had marked preoperative cortical opacities. Eight of the remaining 45 eyes with clear or almost clear cortexes showed a central subcapsular opacity after 1 to 2 years, probably IOL induced. CONCLUSION: Use of the Chiron-Adatomed IOL should be confined to older patients with early cataract until its role as the cause of opacities has been clarified by further observation.

Cataract↗
PubMed1996

Post-traumatic syringomyelia (cystic myelopathy): a prospective study of 449 patients with spinal cord injury.

OBJECTIVES: To assess the incidence of post-traumatic syringomyelia (PTS), to correlate the presence of PTS with its most common signs and symptoms, and to compare results from the Swiss Paraplegic Centre with those reported in the medical literature. METHODS: A total of 449 recent traumatic paraplegic and tetraplegic patients admitted to the Swiss Paraplegic Centre in Zurich between 1 January 1987 and 31 December 1993 were prospectively analysed. Yearly clinical tests with conventional radiographs and additional T1 and T2 weighted images were performed as soon as PTS was diagnosed. RESULTS: Of these 449 patients 20 patients displayed symptoms of PTS (4.45%). Ten non-operated patients remained clinically stable (average time: 37 months). Ten worsened--three refused operation, seven were operated on. Mean worsening time was 97 months. Deterioration was closely related to the enlargement of the cyst whereas in operated patients neurological improvement or stabilisation correlated with collapse of the cyst. CONCLUSIONS: Delay between appearance of the first symptoms of PTS and deterioration making surgery necessary may be long (mean five years in the seven operated patients) underlining the need for regular tests. "Slosh" and "suck" mechanisms could explain cyst enlargement as surgical realignment of the spine resulted in a complete cyst collapse in two of the operated patients (normalisation of CSF flow? ). Cord compression, tense syrinx at the fracture site, and kyphosis seemed to be closely linked to the enlargement of the cyst with subsequent further neurological deterioration.

Adolescent↗
PubMed1996

A novel point mutation in the translation initiation codon of the pre-pro-vasopressin-neurophysin II gene: cosegregation with morphological abnormalities and clinical symptoms in autosomal dominant neurohypophyseal diabetes insipidus.

Autosomal dominant neurohypophyseal diabetes insipidus (ADNDI) is a rare variant of idiopathic central diabetes insipidus. Several different mutations in the human vasopressin-neurophysin II (AVP-NP II) gene have been described. We studied nine family members from three generations of an ADNDI pedigree at the clinical, morphological, and molecular levels. AVP concentrations were measured during diagnostic fluid restriction tests. Coronal and sagittal high resolution T1-weighted images of the pituitary were obtained from affected and healthy family members. PCR was used to amplify the AVP-NP II precursor gene, and PCR products were directly sequenced. Under maximal osmotic stimulation, AVP serum levels were close to or below the detection limit in affected individuals. Magnetic resonance imaging studies revealed the characteristic hyperintense ("bright spot") appearance of the posterior pituitary in two healthy family members. This signal was absent in all four ADNDI patients examined. The coding sequences of AVP and its carrier protein, neurophysin II, were normal in all family members examined. Affected individuals showed a novel single base deletion (G 227) in the translation initiation codon of the AVP-NP II signal peptide on one allele. The mutation in the AVP-NP II leader sequence appears to be responsible for the disease in this kindred, possibly by interfering with protein translocation. The absence of the hyperintense posterior pituitary signal in affected individuals could reflect deficient posterior pituitary function.

Adolescent↗
PubMed1996

Electrophysiology in the locked-in-syndrome.

We investigated five patients with a locked-in-syndrome (LIS) and reported the clinical, electrophysiologic, neuroradiologic, and neuropathologic findings. EEG reactivity was present in two and absent in three cases. Somatosensory evoked potentials (SEP) varied from unilaterally normal to bilaterally absent. We conclude that there is no specific pattern of SEP abnormality characteristic of LIS and that EEG reactivity cannot be taken as a sole measure of consciousness.

Adult↗
PubMed1996

Correlation of MRI, clinical, and electroneuronographic findings in acute facial nerve palsy.

Intratemporal enhancement of (Gd-DTPA) was investigated by an interleaved-overlapping magnetic resonance imaging (MRI) technique in 35 cases of acute facial palsy. In a reference group (normal facial function), enhancement was localized from the ganglion geniculi to the stylomastoid foramen. In cases of acute palsy, the facial nerve enhanced in the meatal fundus independent of etiology (idiopathic, herpetic, or traumatic). In 70% of those with Ramsay-Hunt syndrome, the vestibular and cochlear nerves, the labyrinth, and the sheets of the internal and external auditory canal additionally enhanced. No correlation was found between intensity, extension, and duration of the enhancement and the clinical, intraoperative, or electroneuronographic degree of the facial palsy. The pathogenesis of the Gd-DTPA enhancement of the facial nerve appears to be closely connected with the vascular supply of the fallopian canal and the permeability of the neural sheets.

Adolescent↗
PubMed1996

Intensity of MR contrast enhancement does not correspond to clinical and electroneurographic findings in acute inflammatory facial nerve palsy.

PURPOSE: To determine the value of MR contrast enhancement in predicting the course of acute inflammatory facial nerve palsy and in selecting patients for surgical decompression. METHODS: Six patients with an acute inflammatory incomplete or complete peripheral facial nerve palsy (five idiopathic and one herpetic in origin) had repeated MR imaging studies with and without contrast enhancement, electroneurography, and clinical examinations to establish a connection between the intensity of contrast enhancement on MR images, the clinical condition, and the electrophysiological data. The examinations were performed every second day starting on the first day of admission until clinical recovery was proved by clinical deblockage (spontaneous clinical improvement). The last examination was performed 3 months after the onset of the facial nerve palsy. RESULTS: An abnormal, very intense contrast enhancement of the facial nerve was always present in the distal intrameatal and proximal tympanic segments and in the geniculate ganglion. The labyrinthine segment exhibited a mild to moderate enhancement, and the distal tympanic and mastoid segments showed a moderate to intense enhancement. The intensity of contrast enhancement did not correspond to the severity, duration, or course of the facial nerve palsy, and the electroneurographic data had no predictive value in indicating the severity of the inflammatory process. Three months after clinical recovery, a persistent and more or less unchanged or even slightly more intense contrast enhancement was observed. CONCLUSION: The long-lasting intense contrast enhancement seen in the facial nerve segments of patients who have acute peripheral inflammatory facial nerve palsy is explained by a two-phase breakdown of the blood-nerve barrier.

Adult↗
PubMed1995

The missing temporal crescent.

PURPOSE: We studied clinically the representation of the monocular temporal crescent in the human visual cortex and noted the importance of using the perimetric techniques best suited to detect this visual field defect and to study patients in whom the temporal crescent is missing. METHODS: Goldmann perimetry and high-resolution magnetic resonance imaging were performed in two patients with vascular lesions located in the anterior striate cortex. RESULTS: A monocular visual field defect, the missing temporal crescent, was found on the side contralateral to the lesion. CONCLUSIONS: The perimetric-magnetic resonance imaging correlation is in exquisite agreement with recent information about the representation of the visual field in the human primary visual cortex. Reports of this specific perimetric finding are rare, in part because of underdetection with currently used perimetric techniques that concentrate on the central 30 degrees of the visual field.

Adult↗
PubMed1995

Magnetic resonance imaging and intraoperative frozen sections in intratemporal facial schwannomas.

Seven cases of intratemporal facial schwannoma were assessed by preoperative magnetic resonance imaging (MRI) and intraoperative frozen sections to determine tumor boundaries. These results were then analyzed with respect to gross tumor appearance, under the operating microscope, and final histopathologic diagnosis, with immunostains. Gadolinium-enhanced MRI was helpful in planning the surgical and approach and in defining the extent of tumor involvement relative to the facial nerve. Frozen sections on the other hand were often unreliable in confirming the completeness of resection, frequently overestimating tumor infiltration. Ultimately, tumor-nerve interface, especially in the proximal facial segments, is best judged by its gross intraoperative appearance under high magnification, with the aid of MRI. The difficulty in establishing tumor infiltration in the presence of organized neutral fibers and artifacts is emphasized. Immunohistochemical assays are essential in this regard. Complete tumor removal was achieved in all seven cases, with acceptable functional outcome in those with sufficiently long follow-up.

Adolescent↗
PubMed1995

[Anatomy and pathology of the parotid gland. COrrelation with magnetic resonance tomography].

Due to a very complex embryological development a variety of different tissues are mixed together within the parotid gland. Secondary degenerative metaplastic and regenerative alterations result in additional tissue variety. Epithelial cells of distinct differentiation, lymphatic tissue, partly within lymph nodes, partly in clusters, sebaceous tissue, fat and peripheral nervous tissue may be the origin of a pathological neoplastic or inflammatory intraparotid lesion. MRI is an optimal tool for the delineation of the anatomy of the parotid gland and of various intraparotid lesions and often permits differentiation among malignant and benign neoplastic and inflammatory lesions. The morphology of the different pathological lesions on MRI reflects the underlying histopathology. Due to great interindividual variations in the tissue characterization of a specific intraparotid lesion, great differences in MR morphology have to be expected.

Humans↗